Editing ISO 639 (section)

==Characteristics of individual codes==
Scopes:
* Individual languages
* [[Macrolanguage]]s (Set 3)
* Collections of languages (Sets 2, 5). Some collections were already in Set 2, and others were added only in Set 5:
** Remainder groups: 36 collections in both Set 2 and 5 are of this kind — for compatibility with Set 2 when Set 5 was still not published, the remainder groups do not contain any language and collection that was already coded in Set 2 (however new applications compatible with Set 5 may treat these groups inclusively, as long they respect the containment hierarchy published in Set 5 and they use the most specific collection when grouping languages);
*** The only collection which previously assigned with two-alphabet code is [[Bihari languages|Bihari]] (bh) during the Part 1 era, which deprecated in June 2021.<ref name=":0">{{cite web|url=https://iso639-3.sil.org/about/news/change-part-1-language-code|title=Change to Part 1 Language Code|date=2021-06-14|author=[[SIL International]]|website=ISO 639-3}}</ref>
** Regular groups: 29 collections in both Sets 2 and 5 are of this kind — for compatibility with Set 2, they can not contain other groups;
** Families: 50 new collections coded only in Set 5 (including one containing a regular group already coded in Set 2) — for compatibility with Set 2, they may contain other collections except remainder groups.
* [[Dialect]]s: they were intended to be covered by former ISO 639-6 (proposed but now withdrawn).
* Special situations (Sets 2, 3).
* Reserved for local use (Sets 2, 3). Also used sometimes in applications needing a two-letter code like standard codes in Sets 1 and 2 (where the special code <code>mis</code> is not suitable), or a three-letter code for collections like standard codes in Set 5.

Types (for individual languages):{{Update inline|date=April 2023}}
* [[Living language]]s (Sets 2, 3) (except Sanskrit, all other macrolanguages are living languages)<ref>{{cite web|url=https://iso639-3.sil.org/code_tables/639/data?title=&field_iso639_cd_st_mmbrshp_639_1_tid=All&name_3=&field_iso639_element_scope_tid=76&field_iso639_language_type_tid=All&items_per_page=100 |title=ISO 639 code tables: macrolanguages |website=Sil.org |access-date=2012-08-05}}</ref>
* [[Extinct language]]s (Sets 2, 3) (599,<ref>{{cite web|url=https://iso639-3.sil.org/code_tables/639/data?title=&field_iso639_cd_st_mmbrshp_639_1_tid=All&name_3=&field_iso639_element_scope_tid=All&field_iso639_language_type_tid=41&items_per_page=100 |title=ISO 639 code tables: extinct |website=Sil.org |access-date=2012-08-05}}</ref> 5 of them are in Set 2: <code>chb</code>, <code>chg</code>, <code>cop</code>, <code>lui</code>, <code>sam</code>; none are in Set 1)
* [[Ancient language]]s (Sets 1, 2, 3) (124,<ref>{{cite web|url=https://iso639-3.sil.org/code_tables/639/data?title=&field_iso639_cd_st_mmbrshp_639_1_tid=All&name_3=&field_iso639_element_scope_tid=All&field_iso639_language_type_tid=31&items_per_page=100 |title=ISO 639 code tables: ancient |website=Sil.org |access-date=2019-01-10}}</ref> 19 of them are in Set 2; and 5 of them, namely <code>ave</code>, <code>chu</code>, <code>lat</code>, <code>pli</code> and <code>san</code>, also have a code in Set 1: <code>ae</code>, <code>cu</code>, <code>la</code>, <code>pi</code>, <code>sa</code>)
* [[Historical language]]s (Sets 2, 3) (89,<ref>{{cite web|url=https://iso639-3.sil.org/code_tables/639/data?title=&field_iso639_cd_st_mmbrshp_639_1_tid=All&name_3=&field_iso639_element_scope_tid=All&field_iso639_language_type_tid=46&items_per_page=100 |title=ISO 639 code tables: historical |website=Sil.org |access-date=2012-08-05}}</ref> 16 of them are in Set 2; none are in Set 1)
* [[Constructed language]]s (Sets 1, 2, 3) (23,<ref>{{cite web |url=https://iso639-3.sil.org/code_tables/639/data?title=&field_iso639_cd_st_mmbrshp_639_1_tid=All&name_3=&field_iso639_element_scope_tid=All&field_iso639_language_type_tid=36&items_per_page=100 |title=ISO 639 code tables: constructed |website=Sil.org |access-date=2022-02-07}}</ref> 9 of them in Set 2: <code>afh</code>, <code>epo</code>, <code>ido</code>, <code>ile</code>, <code>ina</code>, <code>jbo</code>, <code>tlh</code>, <code>vol</code>, <code>zbl</code>; 5 of them in Set 1: <code>eo</code>, <code>ia</code>, <code>ie</code>, <code>io</code>, <code>vo</code>)

Individual languages and macrolanguages with two distinct three-letter codes in Set 2:
* Bibliographic (some of them were deprecated, none were defined in Set 3): these are legacy codes (based on language names in English).
* Terminologic (also defined in Set 3): these are the preferred codes (based on native language names, romanized if needed).
* All others (including collections of languages and special/reserved codes) only have a single three-letter code for both uses.